Singh, who represents Sonepur, is in a catch-22 situation as rival RJD has fielded his son-in-law Randhir Singh in the neighbouring Chapra constituency. JD(U) and Congress are also supporting his candidature as secular alliance partners.

BJP has fielded Kanhiaya Singh from the seat which was vacated by Janardan Singh Sigriwal, who won the Lok Sabha poll on BJP ticket.

"It is indeed a difficult situation for me ...Considering my plight the party has shifted me for campaigning to Mohiuddinnagar seat in Samastipur which will also see bye-election on August 21," he said.

Asked if his son-in-law has his blessings, Singh laughed and said over phone from Mohiuddinnagar, "He is mature and has neither approached me nor talked to me about the by-poll."

Randhir Singh is son of former RJD MP Prabhunath Singh.

Asked if his family and supporters were working for BJP or his son-in-law, he said: "Its democracy and everybody has independence to think what is best for him and vote."

In reply to a question about the likely outcome of the by-election in Chapra, Singh said he has no idea as he has been away from the constituency.

Singh had defeated former Chief Minister Rabri Devi to win from Sonepur in the 2010 assembly poll.